We examined whether social isolation and loneliness (1) predict acute myocardial infarction (AMI) and stroke among those with no history of AMI or stroke, (2) are related to mortality risk among those with a history of AMI or stroke, and (3) the extent to which these associations are explained by known risk factors or pre-existing chronic conditions.
Participants were 479,054 individuals from the UK Biobank. The exposures were self-reported social isolation and loneliness. AMI, stroke and mortality were the outcomes.
Over 7.1 years, 5,731 had first AMI, and 3,471 had first stroke. Social isolation and loneliness were associated with higher risk of AMI and stroke. When adjusted for all the other risk factors, the associations were attenuated considerably. In addition, social isolation, but not loneliness, was associated with increased mortality in participants with a history of AMI or stroke in the fully adjusted model.
Isolated and lonely persons are at increased risk of AMI and stroke, and, among those with a history of AMI or stroke, increased risk of death. Most of this risk was explained by conventional risk factors.
Social isolation and health - what are the mechanisms?
According to the loneliness model of Cacioppo, lonely individuals would (1) engage in poorer health behaviours than others, (2) show altered cardiovascular activation, (3) show chronically elevated levels of hypothalamic pituitary adrenocortical activation, and thus lower glucose tolerance, diminished cortisol regulation, poor sleep and decreased cognitive performance, and (4) report more frequent mental health problems. All these four factors are risk factors for increased cardiovascular diseases, diabetes and mortality. This research project aims to investigate the association between social isolation and health and test whether pathways including health behaviours, physiological factors, mental health and socioeconomic position would explain the associations. Study aims to provide knowledge how social isolation affects health, which will help to create better prevention programs to heal individuals who are socially isolated.
We will define social isolation based on the following UK Biobank questions:
709 Number in household
6141 How are people in household related to participant
1031 Frequency of friend/family visits
6160 Leisure/social activities
2110 Able to confide
An individual will be defined as socially isolated if he/she lives alone, doesn't participate in any social activities and can rarely confide to other people. The primary analyses will be performed on all-cause mortality and incidence of major diseases (e.g. coronary heart disease, stroke, cancer and diabetes). In secondary analyses, we will examine whether loneliness is linked with health outcomes (cardiovascular heart disease, diabetes and mortality) through pathways suggested by the loneliness model, including behavioural risks (drinking, smoking, physical activity and diet), physiological risks (blood pressure, obesity, handgrip cholesterol, sleep), mental health (depression and anxiety) and socioeconomic position (education, employment status, income).
Tested using hierarchical regression models, structural equation modeling and bootstrap-models. Full cohort will be used.
|Lead investigator:||Marko Elovainio|
|Lead institution:||National Institute for Health and Welfare|